In Non Patent Literature 1 below, an LED (light-emitting diode) using a GaN substrate having a semipolar principal surface is described. It is stated that this LED is formed on a GaN substrate having the (11-22) plane as a principal surface, has a light-emitting layer with a single quantum well structure comprising InGaN/GaN, and has a light emission wavelength of 600 nm.
In Non Patent Literature 2 below, an LD (laser diode) using a GaN substrate having a semipolar principal surface is described. It is stated that this LD is formed on a GaN substrate having the (10-1-1) plane as a principal surface, has a light-emitting layer with a multiple quantum well structure comprising InGaN/GaN, and has a light emission wavelength of 405.9 nm (blue-violet).